1. Field of the Invention
This invention relates to a camera and more particularly to a circuit for sensing the action of a camera shutter.
2. Description of the Prior Art
Application of electronics to cameras has popularized electrical shutter time control. As a result of this, the exposure precision and the reliability of cameras has been greatly improved over the conventional cameras of the mechanical control type. However, mechanical shutter blades are still in use as shutter members of cameras. It has been impossible, therefore, to insure a camera from difficulties due to mechanical shutter members. For example, there have been occurrences of trouble due to the shutter members remaining inoperative after a shutter release operation and thus causing photographic failure. In view of this, it has become necessary to mechanically detect the actions of shutter members, for example, by means of a count switch of an electronic shutter, or the like, and to find out whether or not the shutter members have normally operated. However, even with such a method, it is still impossible to accurately sense the action of shutter members.
This is so because, when the action of shutter members is to be detected by a count switch as mentioned, the count switch itself tends to get out of order due to its mechanical construction. Therefore, while the shutter members fail to work, the count switch might not indicate this failure of the shutter members. The conventional discriminating or sensing method thus has been unable to always accurately detect the action of shutter members.